Self cleaning filter



April 13, 1965 H. L. WHEELER, JR

SELF CLEANING FILTER 4 Sheets-Sheet l Filed Aug. 6, 1962 INVENTOR HARRY L WHEELER JR.

ATTORNEY Pll 13 1965 H. L. WHEELER, JR 3,178,023

SELF CLEANING FILTER Filed Aug. 6, 1962 4 Sheets-Sheet 2 INVENTOR.

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HARRY L. WHEELER JR.

April 13, 1965 H. L. WHEELER, JR

SELF CLEANING FILTER 4 Sheets-Sheet 3 Filed Aug. 6, 1962 April 13, 1965 H. l.. WHEELER, .JR 3,178,023

CLEANING T R INVENTOR, HARRY L. WHEELERA/Q.

United States Patent O 3,178,023 SELF CLEAN 'G FILTER Harry L. Wheeler, ir., Madison Heights, Mich., assigner to The Bendix lorporation, Madison Heights, Mich., a corporation of Deiaware Filed Aug. 6, i962, Ser. No. Z15,l53 9 Claims. (CL 21d- 143) This invention relates to iiuid filters and more particularly to a self cleaning wire wrapped duid filter.

At the present time, the only self cleaning filters, which are known to be commercially available, consist of a stack of metal plates between which are provided a series of rotating scrapers very much like the alternate rotor and stator plates of a lvariable condenser. Such filters have several inherent disadvantages. In the iirst place, the degree of filtration which can be achieved is limited by the thickness of metal in the rotating scrapers which thickness is in turn dictated by structural stiiness considerations. Secondly, since the extracted contamination in this type of tilter must drip down the side of the ilter, the natural ilow of iiuid into the filter from outside-in will cause this contamination which has just been removed to be driven back into the lter. Thirdly, the scraper type of iilter tends to drive contamination into the space between the plates, or to pulverize it.

Accordingly, it is an object of this invention to provide a self cleaning iluid filter which does not possess the above mentioned inherent disadvantages.

Another object of this invention is to provide a self cleaning iluid filter which utilizes a movable stranded wire as part of a iiltering surface wherein contaminants which adhere to said wire are carried by said wire away from the surface at which filtration is occurring before the contaminants are wiped from the wire into a sump.

More specifically, it is an object of this invention to provide a self cleaning wire wrapped fluid iilter which includes a rotating perforated and threaded cylindrical drum having its perforations located at the root of the thread formed thereon, a stranded wire which is wrapped around the drum and is located between adiacent crests of the thread, an idler pulley arranged so that the stranded wire will pass oli the drum, around the pulley and back onto the drum, and avmechenism located between the drum and pulley which scrapes accumulated contamination from the stranded wire. In this arrangement, filtration is accomplished when the uid passes through the interstices formed between the wire and the sides of the thread and thence through the perforations of the drum.

Another object of this invention is to provide a novel shelf cleaning wire wrapped iiuid filter which has a relatively high filtration eiciency and is relatively inexpensive to fabricate.

A further object of this invention is to provide a self cleaning wire wrapped duid filter of the type described in which the stranded wire is in contact with a single rotating drum at all points except that at which it is removedfrom the drum for cleaning.

A still further object of this invention is to provide a self cleaning wire wrapped duid tiiter oi the type de scribed in which the stranded wire does not move relative to the drum, except at the point where it is removed from and rewound on the drum. As a result, there is no relative movement of parts at the etlective iiltering surface and the pores are clearly defined and nonvariable.

Another object of this invention is to provide a novel porous iltering surface whose porosity is determined by a stranded wire lying in a helical groove formed on the surface of a cylindrical drum which has perforations extending therethrough and located at predetermined intervals along the root of the helical groove.

ldzd Patented Apr. i3, 1955 ICC A further object of this invention is to provide a uid filter of the type described Whose porosity will be relatively uniform and predictable for a given size of thread and stranded wire coniiguration and whose porosity can be easily increased or decreased simply by changing the size and/0r conguration of the stranded wire.

The above and other objects and features of this invention will become apparent from the following description taken in connection with the accompanying drawings which form a part of this disclosure and in which:

FIGURE l is a view partially in section showing a ilter unit constructed in accordance with my invention; l

FIGURE 2 is a sectional View taken along line 2-2 of FiGURE 1;

FIGURE 3 is a sectional view taken along line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged view of the circumscribed portion of FIGURE l;

FIGURE 5 is a sectional View taken along line 5 5 of FIGURE 4;

FIGURE 6 is a sectional view taken along line 6 5 0f FIGURE 4; and l FIGURE 7 is a schematic perspective View of another embodiment of my invention.

y Referring to the drawings, it will be noted that numeral 1t) indicates a pressure tight box-like housing having an inlet port 12 and an outlet port 14 for permitting ow of fluid therethrough. A hollow cylindrical drum 16 is located within the housing and is operatively connected thereto by a pair of fittings 1S and 20 which permit the drum to be rotated about its axis. One of the ttings I8 includes a passage ZZ which communicates the inside of the drum with outlet port i4, while the other fittingl is operatively connected to a Suitable motor (not shown) through means of a pin 24. The drum may be rotated either by an electric motor or by a hydraulic motor powered by the iluid which is being iiltered. Although in the preferred embodiment a motor is used to either continuously or intermittently rotate the drum, it should be understood that under certain conditions the elimination of the motor may be desirable and that the drum could be manuallyy rotated at predetermined intervals. The outer cylindrical surface of the drum is threaded, as shown FIGURE 1 and 4, so that a continuous helical groove or thread 26 extends from one end of the drum to the other. Referring to FIGURES 4, 5 and 6, it will be noted that at predetermined intervals along the root 27 of the-thread or helical groove 26 are located a plurality of substantially rectangular drum ports 2S which are formed by broaching a series of axial grooves 30 along the inner surface of the drum so that the axial grooves intersect the minor diameter of the threads. If desired, the same eiiect could be achieved by other means such as: by forming the drum, helical groove, and the drum ports through means of a casting process, or by wrapping a perforated cylinder with a solid wire which is helically wound therearound and spaced to form effectively a' helical groove between the convolutions of solid wire.

Radially spaced from the drum 16 and parailel to the axis thereof is an idler shaft 32 which is operatively connected to the housing tti by a pair of idlcrarms 34 each of which has one end pivotally connected to the housing by a pin 36 and theother end arranged to receive a tension spring 3d for a reason to be subsequently explained. The idler shaft $2 is pinned to the idler arms 3d at a point 4t) intermediate the ends of said arms. An idler 16 so that it is located between the crests 46 of the thread or in other words in the lhelical groove 26. This wire is Y the stranded wire are fixedly connected to the drum by suitable means such as screws 48. Filtration occurs by passing fluid from outside the drum to inside the drum via the interstices formed between the stranded'wire and the sides ofthe helical `groove 26, and the drum ports 28. The degre of filtration is controlled entirely by the number of strands in the stranded wire, by the size ofthe individualv strands, and by the number of twist-s per linear inch ofthe stranded' wire. The threading `on the exterior of the drum is such that with the strand size selected, the stranded wire restsrmly against the sides of the helial groove. The rectangular drum ports 28 are cu-t so that they` do not intersect the sides of the helical groove 26 above the line of contact between the strand wire and the sides of the helical groove. l

The strand wire used in connection with the invention may be composed of two or more strands which prefer-Y a-bly are helical-ly twisted to in effect form helically disposed protu'berances on the surface of the stranded Wire. The effective diameter vof the wire will be determined by the size and number of strands used, and will be equal to the diameter of the smallest circle circumscribing al1 of the strands in the wire. Groupings of threeor seven strands are most Vsatisfactory because they produce the` yhighest density packing and the most predictable pore sizes. The more predictable pore sizes are'due to the ffact that the cross-section for a given helically twisted three stranded or seven 'stranded wire is identical at any point, andthe centers of the strands define an equilateral polygon, e.g. in the case of a three stranded wire an equilateral triangle and in the case of a seven stranded wire an equilateral hexagon, since the seventh strand simply Vserves as a core for therother six strands.

Rotation of Vthe drum 16 about its axis will causeY the stranded wire 44 to progressively leave the drum and pass along the pulley 42 before returning to the drum..

With the ends of the stranded wire fixed to the drum, virtually all of the stranded wire, which is used as part orf the effective filtering surface on the drum, passes around the pulley, thereby causing the pulley to move from one end of the idler shaft 32 to the other. When `the idler Vpulley has reached the end olfV its travel it .will contact either a limit switch or a valve push rod 50 which will reverse the direction of thedrive of the motor. The drum will then reverse its direction of rotation and the pulley will return Vto the opposite end of the idler shaft where a similar limit switch'is locatedi Other methods of reversing the motor may be used. *For example, a pre-set counter may be utilized which Iwill allow the motor to make a given number of turns in one direction then cause it to automatically reverse and make an equal number of turns in the opposite direction. Another method of accomplishing reversal would beto utilize a simple type of gear shift such as is used on lathes to reversethe direction of carriage travel.

In order to provide a self cleaning action a wiper shieldV Vleave behind it exposed drum ports 28 which will have no filtering effect, the center portion of the wiper shield 52 which rests against the drum is raised to form a ridge or male, thread 54 which mates with that portionv of the hel-ical groove which is not covered by the stranded wire.

In addition, 'sinceV the wiper shield is sufliciently wide to cover at least three of the threads, as shown in FIG. l, the abut-ments to this male thread on the shield edge will rest on the two wraps of stranded wire which are adjacent to the empty drum thread or on the adjacent crests of the thread, depending on which the highest. Consequently, as the drum rotates, the wiper shield will move along with the wire leaving the drum, said Wiper shield being driven forward by the action of the female thread formed 4on the drum against the nrale thread formed on the wiper shield, and by the movement of the wire itself. In addition to the driving aspects' of the central guiding ridge 5470i theV wiper shield, the ridge serves to wipe clear any contamination which may have lodged in the root of the thread. In order to facilitate the cleaning of the wiper shield, if desired, the filter inlet could be arranged lso that the wiper shield is constantly being washed by fresh fluid. The stranded wire is maintained under tension through means of tension springs 38 which are attached to idler arms 34.

In the event that a change in the degree of filtration is required, or in the event that the stranded wire becomes worn, the only element that need be replaced is theV stranded wire itself. Since the normal mounting of the filter is such that the idler shaft is below the drum and the sludge which is removed from the stranded wirewill fall into .the sump below the idler shaft, the sump could be provided with a device (not shown), such as an Archimedes screw with suitable pressure locks, for removing such sludge.

Those acquainted with this art will readily understand that the invention herein set forth is not necessarily limited to the precise and exact details presented and that fvariofus changes and modifications may be resorted to without departing from the spirit of the invention. For example it will be noted from the schematic View shown in VFIGURE 7, wherein like parts Vare'designated by the `same number plus added thereto, that the idler shaft 132'couldfbe threaded to the wiper shield 1512 and gear driven from the drum 116 through gears 1217 and 1119 so that movement of the wiper shield is positive at a'll times.

The idle-r pulley 142 would then be mounted on the side of the shield rather than on the idler shaft through means on a pin 143. Accordingly, applicant does not desire to be limited to the specific details described herein, primarily .for .purposes of illustration, but instead desires protection falling within the scope ofthe appended claims.

Having thus described Vthe various features of the invention, what I claim as new and desire to secure by Letters Patent is:

1. A self cleaning wire wrapped fluid filter comprising a housing having an inlet port and an outlet port for permitting flow of fluid therethrough, a hollow cylindrical drum located within said housing, said Vdrum having a helical thread formed on the outer surface thereof and a plurality of drum portslocatedrat predetermined intervals along the root of said thread, fitting means located at each Y endof said drum along the axis thereof for operatively connecting said drum to said housing, passage means located in one of said fitting means for communicating the inside of said drum with said outlet port, an idler shaft operatively connected to said housing, said idler shaft being radially spaced from said drum and parallel to the axis thereof, an idler pulley rotatable on said idler` shaft and slidable therealong 4from a first end position-to a second end position, a stranded wire wrapped around said drum and located between adjacent crests of said thread for permitting flow of fluid from outside said drum to inside said drum via the interstices formed between the stranded Wire and the sides'of said thread, said stranded wire having the major portionV thereof continuously wrapped around said drum andthe remaining portion f thereof spaced therefrom and passing around said pulley, means for xedly connectingV the ends of said stranded wire to said drum, means operatively connected tothe other of said fitting means for rotating said drum about its axis and causing said stranded wire to progressively leave the drum and pass along said pulley before returning to said drum, a shield-like wiper member located between said drum and said pulley and between two portions of said stranded wire for guiding said wire to and from said drum and for removing contaminants from the wire as it passes onto and off of said pulley, ridge means formed on said wiper member for continuously mating with a portion of said thread which is not covered by the stranded Wire and for removing any contaminants therefrom as said drum rotates, and resilient means opatively connected to said idler shaft for maintaining said stranded wire under tension.

2. A self cleaning wire Wrapped liuid iilter as defined in claim 1 which includes means for reversing the direction of rotation of said drum when said idler pulley reaches one of its end positions.

3. A self cleaning wire Wrapped uid filter comprising a housing having inlet and outlet ports for permitting ow of fluid therethrough, a hollow cylindrical drum located within said housing and operatively connected thereto along the axis of said drum, said drum having a helical groove formed on the outer surface thereof and a plurality of perforations located at predetermined intervals along said helical groove, passage means for communicating the inside of said drum with said outlet port, an idler shaft radially spaced from said drum and parallel to the axis thereof, an idler pulley rotatable on said shaft and slidable therealong, a stranded wire wrapper around said drum and located in said groove for permitting flow of fluid from outside said drum to inside said drum via the interstices formed between the stranded wire and the sides of said groove, said stranded wire having the major portion thereof continuously wrapped around said drum and the remaining portion thereof spaced therefrom and passing around said pulley, means for iixedly connecting the ends of said stranded wire to said drum, means for rotating said drum about its axis and causing said stranded wire to progressively leave the drum and pass along said pulley before returning to said drum, wiper means located between the drum and the pulley for removing contaminants from the wire as it passes onto and off of said pulley, said wiper means having ridge means formed thereon for mating with a portion of said drum groove not covered by the stranded wire, and means operatively connected to said idler shaft for maintaining said stranded wire under tension.

4. A self cleaning wire wrapped duid filter comprising a housing having inlet and outlet ports for permitting iiow of fluid therethrough, a hollow cylindrical drum iocated within said housing and operatively connected thereto along the axis of said drum, said drum having a helical groove formed on the outer surface thereof and a plurality of drum ports located at predetermined intervals along said helical groove, passage means for communicating the inside of said drum with said outlet port, a threaded idler shaft radially spaced from said drum and parallel to the axis thereof, a wiper shield threaded onto said idler shaft, an idler pulley pinned to said shield, said pulley being rotatable about said pin, a stranded wire wrapped around said drum and located in said groove for permitting flow of iuid from outside said drum to inside said drum via the interstices formed between the stranded wire and the sides of said groove, said stranded wire having the major portion thereof continuously Wrapped around said drum and the remaining portion thereof spaced therefrom and passing around said pulley, means for iixedly connecting the ends of said stranded wire to said drum, means for rotating said drum about its axis and causing said stranded wire to progressively leave the drum and pass along said pulley before returning to said drum, said last named means being operatively connected to said idler shaft to cause rotation thereof and consequent movement of the wiper shield and pulley axially with respect to said drum as said stranded wire passes along said pulley, and wiper means located on said shield for removing contaminants from the wire as it passes onto and off of said pulley.

5. A self cleaning wire wrapped Huid iilter as defined in claim 4 wherein said means for rotating said drum and idler shaft includes a pair of meshing gears one of which is operatively connected to said drum and the other of which is operatively connected to said idler shaft.

6. A self cleaning wire Wrapped Huid filter comprising a housing having inlet and outlet ports for permitting flow of fluid therethrough, a hollow cylindrical drum Y located within said housing and operatively connected thereto along the axis of said drum, said drum having a helical groove formed on the outer surface thereof and a plurality of drum ports located at predetermined intervals along said helical groove, pulley means operatively connected to said housing, a stranded Wire wrapped around said drum and located in said groove for permitting flow of uid from outside said drum to inside said drum via the interstices formed between the stranded Wire and the sides of said groove, said stranded Wire having the major portion thereof continuously wrapped around said drum and the remaining portion thereof spaced therefrom and passing around said pulley means, means for ixedly connecting the ends of said stranded Wire to said drum, means for rotating said drum about its axis and causing said stranded wire to progressively leave the drum and pass along said pulley means before returning to said drum, wiper means for removing contaminants from said stranded wire as it passes onto and oft of said pulley, and means for maintaining said stranded wire under tension.

7. A self cleaning wire wrapped fluid filter comprising a rotatable hollow cylindrical drum having a helical groove formed 0n the outer surface thereof, said drum having a plurality of ports located therein at predetermined intervals along the root of said helical groove, a stranded wire having each end thereof iixedly connected to said drum, said wire being wrapped around said drum and located in said groove for permitting flow of uid from outside said drum to inside said drum via the interstices formed between the stranded wire and the sides of said groove, means for maintaining said wire under tension and for progressively permitting a portion of same to leave said groove and return thereto as said drum rotates, and means for removing contaminants from that portion of the stranded wire which has left said groove and that portion of said groove which is not covered by said stranded wire.

8. A self cleaning wire wrapped iluid filter comprising a rotatable hollow cylindrical drum having a helical groove formed on the outer surface thereof, said drum having a plurality of ports located therein at predetermined intenvals along the root of said helical groove, a stranded wire wrapped around said drum and located in said groove for permitting flow of iiuid from outside said drum to inside said drum via the interstices formed between the stranded wire and the sides of said groove, means for progressively permitting a portion of said stranded wire to leave said groove and subsequently return thereto as said drum rotates, and means for removing contaminants from that portion of the stranded wire which has left said groove.

9. A self cleaning wire Wrapped fluid filter comprising a rotatable hollow cylindrical drum having a helical thread formed on the outer surface thereof, said drum having a plurality of ports located therein at predetermined intervals along the root of said thread, a wire Wrapped around said drum and located between adjacent crests of said thread for permitting flow of fluid from outside said drum to inside said drum via the interstices formed between said wire and the sides of said thread, means for progressively permitting a portion of said wire to leave said thread and subsequently return thereto as said drum rotates, and means for removing contaminants Vfrom that portion ofthe wire which has lefty the thread 1,880,005 9'/ 32 Y Wright et a1. 210-'401'X and that portion ofthe thread which is not covered by v 2,247,460 l7/41l 'Wright 210-410 X` said Wire. Y 2,820,549 1/58 Belke ,210-4971 X Y E RfrencesvCited by the Examiner 5, .Y FOREIGN. PATENTS 452,344 11/48 Canada. 342 V038 SThATES PATENTAZ 158 4 X 458,005 12/36 Great Britain, v

ug v Y v 776975 12/04 Wheaton 242 158.4 GEORGE D. MITCHELL, Przmary Examiner.

1,435,425. 3/24 Myeae l242-4584 HERBERT L. MARTIN, Examiner. 

1. A SELF CLEANING WIRE WRAPPED FLUID COMPRISING A HOUSING HAVING AN INLET PORT AND AN OUTLET PORT FOR PERMITTING FLOW OF FLUID THERETHROUGH, A HOLLOW CYLINDRICAL DRUM LOCATED WITHIN SAID HOUSING, SAID DRUM HAVING A HELICAL THREAD FORMED ON THE OUTR SURFACE THEREOF AND A PLURALITY OF DRUM PORTS LOCATED AT PREDETERMINED INTERVALS ALONG THE ROOT OF SAID THREAD, FITTING MEANS LOCATED AT EACH END OF SAID DRUM ALONG THE AXIS THEREOF FOR OPERATIVELY CONNECTING SAID DRUM TO SAID HOUSING, PASSAGE MEANS LOCATED IN ONE OF SAID FITTING MEANS FOR COMMUNICATING THE INSIDE OF SAID DRUM WITH SAID OUTLET PORT, AN INLER SHAFT OPERATIVELY CONNECTED TO SAID HOUSING, SAID IDLER SHAFT BEING RADIALLY SPACED FROM SAID DRUM AND PARALLEL TO THE AXIS THEREOF, AN IDLER PULLEY ROTATABLE ON SAID IDLER SHAFT SAID SLIDABLE THEREALONG FROM A FIRST END POSITION TO A SECOND END POSITION, A STRANDED WIE WRAPPED AROUND SAID DRUM AND LOCATED BETWEEN ADJACENT CRESTS OF SAID THREAD FOR PERMITTING FLOW OF FLUID FROM OUTSIDE SAID DRUM TO INSIDE SAID DRUM VIA THE INTERSTICES FORMED BETWEEN THE STRANDED WIRE AND THE SIDES OF SAID THREAD, SAID STRANDED WIRE HAVING THE MAJOR PORTION THEREOF CONTINUOUSLY WRAPPED AROUND SAID DRUM AND THE REMAINING PORTION THEREOF SPACED THEREFROM AND PASSING AROUND SAID PULLEY, MEANS FOR FIXEDLY CONNECTING THE ENDS OF SAID STRANDED WIE TO SAID DRUM, MEANS OPERATIVELY CONNECTED TO THE OTHER OF SAID FITTING MEANS FOR ROTATING SAID DRUM ABOUT ITS AXIS AND CAUSING SAID STRANDED WIRE TO PROGRESSIVELY LEAVE THE DRUM AND PASS ALONG SAID PULLEY BEFORE RETURNING TO SAID DRUM, A SHIELD-LIKE WIPER MEMBER LOCATED BETWEEN SAID DRUM AND SAID PULLEY AND BETWEEN TWO PORTIONS OF SAID STRANDED WIRE FOR GUIDING SAID WIRE TO AND FROM SAID DRUM AND FOR REMOVING CONTAMINANTS FROM THE WIRE AS IT PASSES ONTO AND OFF OF SAID PULLEY, RIDGE MEANS FORMED ON SAID WIPER MEMBER FOR CONTINUOUSLY MATING WITH A PORTION OF SAID THREAD WHICH IS NOT COVERED BY THE STRANDED WIRE AND FOR REMOVING ANY CONTAMINANTS THEREFROM AS SAID DRUM ROTATES, AND RESILIENT MEANS OPATIVELY CONNECTED TO SAID IDLER SHAFT FOR MAINTAINING SAID STRANDED WIRE UNDER TENSION. 